Effect of an Electric Field on the Texture and Microstructure Evolution during Annealing of High Reduction Cold-Rolled Ni

Abstract:

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The influence of an electric field on the annealing of high purity (99.999%) cold rolled
nickel has been investigated. Annealing was carried out for 2 hours at temperatures between 300oC
and 800oC with and without an electric field of strength 2.0KVcm-1. The microstructure and fraction
of cube texture resulting were characterized using electron backscattering pattern (EBSP) technique.
Annealing in an electric field leads to somewhat smaller average values of the cube fraction and grain
sizes compared to annealing without an electric field. The highest temperature (800oC) annealing in
an electric field results in microstructures with a lower fractional twin boundary length.

Abstract: Annealing is an important mechanism of microstructural modification both in rocks and
metals. In order to relate directly changes in crystallographic orientation to migrating boundaries the
researcher has the option to investigate either samples where the grain boundary motion can be
directly tracked or a series of samples exhibiting successively higher degrees of annealing.
Here we present results from rock samples collected from two well characterised contact
aureoles (a volume of rock heated by the intrusion of a melt in its vicinity): One quartz sample in
which patterns revealed by Cathodoluminescence (CL) indicate the movement of grain boundaries
and a series of calcite samples of known temperature history. Electron backscatter diffraction
(EBSD) analysis is used to link the movement of grain, twin boundaries and substructures with the
crystallographic orientation / misorientation of a respective boundary.
Results from the quartz bearing rock show: (a) propagation of substructures and twin
boundaries in swept areas both parallel and at an angle to the growth direction, (b) development of
slightly different crystallographic orientations and new twin boundaries at both the growth
interfaces and within the swept area, and (c) a gradual change in crystallographic orientation in the
direction of growth. Observations are compatible with a growth mechanism where single atoms are
attached and detached both at random and at preferential sites i.e. crystallographically controlled
sites or kinks in boundary ledges. Strain fields caused by defects and/or trace element incorporation
may facilitate nucleation sites for new crystallographic orientations at distinct growth interfaces but
also at continuously migrating boundaries.
Calcite samples show with increasing duration and temperature of annealing: (a) systematic
decrease of the relative frequency of low angle grain boundaries (gbs), (b) decrease in lattice
distortion within grains, (c) development of distinct subgrains with little internal lattice distortion,
(d) change in lobateness of gbs and frequency of facet parallel gbs and (e) change in position of
second phase particles. These observations point to an increasing influence of grain boundary
anisotropy with increasing annealing temperature, while at the same time the influence of second
phase particles and subtle driving-force variations decrease.
This study illustrates the usefulness of using samples from natural laboratories and combining
different analysis techniques in microprocess analysis.

Abstract: The development of texture and grain boundary character are researched for a boron bearing IF steel after recrystallization annealing for different times at 810°C. The results show that the main texture components are {111}<110> and {111}<112> after the cold rolling samples annealing different times. The maximal volume fraction of <111>//ND texture is about 78% for the sample annealing for 120sec. The main CSL boundaries are ∑3，∑5，∑7，∑9，∑11，∑13b and ∑17b. And the ∑3 grain boundary increase with increasing the annealing times from 60sec to 180sec.

Abstract: The Plane Strain Compression and Static Recrystallisation Textures of BCC Metals Have Been Simulated Using a Coupled 3D Crystal Plasticity Finite Element (CPFE)-Single Phase Field (PF) Model Using an Interstitial-Free (IF) Steel as an Example. the Recrystallisation Nucleation Is Modelled Based on the Orientation Dependent Recovery (ODR) Theory which Assumes that Deformation Texture Components with a Relatively High Number of Slip Systems Activated during the Plane Strain Compression Undergo a Faster Recovery Process during the Subsequent Annealing due to the Cross Slip of Dislocations and as a Result Will Nucleate Earlier than Others. the Growth of Strain-Free Grains Is Simulated Using the Mis-Orientation Angle Dependent Grain Boundary Energy and Interface Mobility. A Linear Interpolation Method Is Adopted to Map the Data between the CPFE Model of Deformation and the Single PF Model of Recrystallisation. Simulated Results Show a Qualitative Agreement with the Typical Rolling and Annealing Textures Measured Experimentally for BCC Metals. Apart from the Texture and Grain Structure Formed during Deformation and Annealing, the Softening Fraction Can Also Be Simulated Using the Developed Model.

Abstract: In the present study, a modified cellular automaton CORe (Cellular Operator for Recrystallization) was used to predict the recrystallization (RX) texture and microstructure of 70% cold rolled commercial AA8079L alloy at 300°C. The nucleation of the Cube orientation is of considerable scientific interest since the Cube texture component influences significantly the anisotropy of material properties. Experimental data collected during this investigation were used for subsequent modeling. By studying the annealed material by EBSD, an average nucleation rate at Cube bands was established and used in the model. The simulated microstructure reveals, in general, good agreement with experiment. The texture prediction shows the right tendency, but the modeled intensity of the Cube texture is about 2 times smaller than in experiment.

Abstract: The recrystallization behavior of the cold rolled 3%Si nonoriented electrical steel at different temperatures is investigated by OIM(Orientation Imaging Microscopy). The results show that the recrystallization process and texture of 3%Si nonoriented electrical steel at different temperatures are determinated by different recrystallization mechanisms. At low annealing temperatures, the formation of recrystallization texture in this specimen can be explained by the mechanism of oriented nucleation theory, but at higher annealing temperatures, the formation of recrystallization texture in this specimen can be explained by the mechanism of oriented growth theory, the twin nucleation mechanism may penetrate the whole recrystallization process.